When property owners in Hamilton County and Chattanooga open their mailboxes this week, they'll likely find a tax bill or two.

County Trustee Bill Hullander plans to have about 120,000 dark-green bills in the mail by Wednesday. The bills include real property taxes for the county and all municipalities except Chattanooga, Lookout Mountain and Signal Mountain.

Chattanooga will mail about 55,000 bills of its own on Wednesday or Thursday, said City Treasurer Gayle Keown. Those will include real and personal property taxes and water-quality fees.

"If someone pays for their own taxes and they don't have a bill by the end of October, they should give us a call," Keown said. "It's the taxpayer's responsibility to get their bill."

Those whose mortgage accounts are in escrow shouldn't expect anything in the mail, because those bills will go directly to mortgage companies, she said. That applies to about 40,000 properties in the county and about 27,000 properties in the city, she said.

This year will be a bit different for owners of multiple properties in the county. Those who own three or more parcels will receive a single envelope containing all of their real property bills with a cover sheet listing them.

"In the past, we've always just sent out and mailed a bill for each piece of property," Hullander said. "We feel like it's going to save some [money] because of not having to do so much postage."

Several years ago, the city consolidated some of its billing, Keown said, but Chattanooga only groups together bills for owners of 10 or more properties.

In anticipation of property-tax time, the trustee's two office locations are now open an extra hour each day -- from 7:30 a.m. to 4:30 p.m., Hullander said. Residents also can make payments online, but a 2.75 percent convenience fee will be tacked on.

Payments are due each year by the end of February. In 2012, which is a leap year, the final day will be Feb. 29. Residents may begin paying their bills as soon as they receive them, though the official payment period begins Oct. 1.

Hamilton County will continue its program of allowing residents to make incremental payments. Prior to last year, residents could only make payments equaling the full amount assessed. The new partial-payment program began in the last tax year and yielded $1.3 million in additional revenue, officials said.

Residents choosing to make multiple county payments should keep in mind that they must pay a monthly 1.5 percent penalty on any remaining balance left on March 1, Hullander said.

Chattanooga is launching the partial payment program for the first time this year, Keown said. Though partial payments are allowed at City Hall, full payments are still required at the First Tennessee Financial Centers that take tax bill payments for the city.

Chattanooga will allow a maximum of one partial payment per calendar month, Keown said, and those payments must be for a minimum of $50.

For Hamilton County, the total cost this year for paper, printing, envelopes, processing and posting bills is $52,374.44, Hullander said.

Estimating the city's costs is more difficult because the city prints, processes and mails its bills in-house, Keown said.

This round of county bills will not include personal property taxes for business equipment and furniture. Those will come later, Hullander said. They'll also be a new color -- orange.